What piece of equipment have you added to your kit that made a surprising difference in your brew day?
Mine was a digital thermostat with an alarm feature. Once I started using that everything just felt so much more precise.
For me so far, it's the 5G Igloo cooler I converted to a mash tun. Also the wort chiller i just made a few weeks ago.
My wort chiller. It used to take me over a half hour to cool a 2.5G batch in a sink of cold water. With my chiller I can cool a full 5 gallon boll in just over twenty minutes.